Local area network concentrators also commonly referred to as hubs, intelligent hubs, or switching hubs have come into wide use, to support networks ranging from one that connects a relatively small number of users, servers, devices, etc. to one that connects thousands of users, servers and devices spread over different geographic areas to form an enterprise network. Local area network concentrators allow the network manager to install media modulus that support different protocols (e.g., ethernet, token ring, FDDI) and different media (e.g., fiber optics, twisted pair) to satisfy the networking needs. Local area network concentrators also allow management of the local area network connections and provide information as to status of the network. Because networks are an increasingly critical part of a company's infra-structure, key feature of such a switching hub is the need to keep the hub operational and to keep the local area network up and running, even if various components of the network fail or various components of the hub fail.
A network manager continually contends with increasing demands on the network, due to the increasing number of applications and users of the network. To satisfy these growing demands, the network manager must be able to scale the network by hot installing more media modules to support more users or new modules supporting higher bandwidth into the hub while it is operational. To meet the power needs of newly installed modules in the hub, the network manager must also be able to scale the hub's power capacity by hot installing additional power supply elements into the hub while it is operational. Since the switching hub may already be supporting numerous network users potentially performing mission critical applications, the network manager can not afford to shutdown the hub and the network it carries. The alternative is hot installation of hub upgrades (modules or power supply elements) with the resultant risk of power overload and hub shutdown. This invention prevents this scenario from occurring.
Networking technology also continues to evolve. Modules continue to be developed that will operate within the switching hub that support higher speed protocols, internetworking, and more advanced features, all in an attempt to satisfy the ever increasing network bandwidth demands. Hence, to accommodate future modules operating in the hub, this invention provides a generic, automated means of managing power within the switching hub without having to perform hardware or software upgrades to the implementation every time a new module is introduced. A highly desired goal is to accommodate and protect any future scaling that the network manager may make in the networking equipment.
Providing a local area network switching hub (concentrator) which is active and running 100% percent of the time is a long sought after goal. Local area networks must be up and running in order that communication over the network can take place. One obvious point of failure is the possibility of a power problem at the switching hub, thereby disrupting all links connected by modules to the switching hub.
The use of redundant elements is well established as a means for avoiding down time. Often, lines to and from the stations are provided in a redundant manner (transmission, reception lines). Redundant power elements and redundant controller elements are also generally known. This is an extra or additional power supply which is held in waiting as a back-up power supply, in case of the failure of the primary power supply.
Often, local area networks are established using a switching hub and are later modified. Further, the power requirements of newer modules continues to change such that systems which are set up with a redundant power supply, often do not have the requisite power to be fault tolerant. That is, failure of the power supply also occurs in situations where a full backup power supply is not available or is not sufficient for the connected modules.
In a hub containing multiple power supply elements, the failure of a power supply element will result in one of 2 outcomes: if the available power at the time of the power supply element failure is more than the amount that the power supply would have been providing, then there is no net change to the power state of the modules installed in the hub. However, if the available power at the time of the power supply element failure is less than the amount that the power supply would have been providing, then a power overload condition exists (i.e., the power required by the power-enabled modules in the hub exceeds the power provided by the remaining operational power supply elements). If no action is taken, then the remaining operational power supply elements may shut-down due to the overload, thereby disrupting all links to modules installed within the hub. The hub remains shut-down until the network manager can get to the hub and replace the failed power supply element. This invention prevents a hub shut-down by automatically sensing the failure of a power supply element and automatically power-disabling individual modules installed in the hub until the power deficit is erased. This is performed without human intervention and ensures that as many of the modules installed in the hub are powered-up as possible. It is a better trade-off to temporarily lose some part of the network versus losing the entire network due to a total hub shut-down.
Similarly, the failure of one or more hub cooling fans or the failure of the wiring closet cooling may cause a hub overheat condition to occur. If no action is taken, then there is a risk that components of power-enabled modules installed in the hub will be damaged due to temperatures exceeding their maximum ratings. In this case, even if the overheat condition is fixed, the network manager must contend with replacing expensive, and potentially mission critical, modules thereby increasing network down-time. This invention prevents this scenario from occurring by automatically detecting the hub overheat condition and automatically power-disabling installed modules to alleviate the overheat condition and prevent damage to expensive, mission-critical modules. This is performed without human intervention and ensures that as many of the modules installed in the hub are powered-up as possible. It is a better trade-off to temporarily lose some part of the network versus losing some part of the network for a longer period due to permanent damage to one or more modules installed in the hub.
For both power supply element failures and hub overheat conditions, this invention accommodates future (as yet to be designed) modules without any updates to the hardware or software implementation.